Assessment of bilateral lower limb lymphoedema: the use of bioimpedance spectroscopy

Purpose: Assessment of bilateral lower limb lymphoedema presents difficulties as there is no unaffected limb for comparison. This study aimed to establish the utility of bioimpedance spectroscopy (BIS) ratios for diagnosing bilateral leg lymphoedema and explored BIS’s potential to differentiate between leg lymphoedema and lower limb swelling. Methods: A cross-sectional study assessed bilateral leg lymphoedema (n = 98), self-ascribed bilateral leg swelling (n = 52), healthy study (n = 52) and database controls (n = 45) using BIS. Device-derived L-Dex scores were compared, and inter-limb control tolerance ellipses were calculated for lymphoedema and self-ascribed swelling groups. Receiver-operating characteristic (ROC) curves determined sensitivity and specificity. Results: Extracellular, intracellular, and total fluid resistances were significantly greater in arms than legs. Arm-to-leg ratios were larger in the lymphoedema group irrespective of leg dominance. Between 26.5% and 67.3% of participants in the bilateral lymphoedema group were classified as having lymphoedema using cutoff thresholds of 10 and 6.5 units, respectively. L-Dex ROC analysis showed area under the curves between 0.75 and 0.80. Conclusion: BIS is sensitive in assessing overall extracellular volume but not specific lymph volume compartments. An integrated approach combining clinical history with BIS is crucial for diagnosing bilateral leg lymphoedema.